Japanese Patent Kokai Publication No. JP-P2008-310876A (Patent Literature 1) discloses a technology that reduces the write time of a spin transfer torque magnetization switching type magnetic random access memory (STT-RAM: Spin-Transfer Torque Random Access Memory). The technology disclosed in Patent Literature 1 writes to an applicable memory cell in the direction of a first current requiring a longer write time before write data is determined in order to reduce the write time of a magnetic random access memory. Then, after the write data is determined, the current in the first direction is kept supplied to the memory cell written in the first current direction, and the direction of the write current for a memory cell written in a second current direction, the write time of which is relatively short, is changed to the second direction. For instance, the write in the first current direction inverts the magnetization direction of a fixed layer and a free layer in a magnetic tunnel junction (MTJ) element from a parallel state to an antiparallel state. The write in the second current direction inverts the magnetization direction of the fixed layer and the free layer from the antiparallel state to a parallel state.
The disclosure of Patent Literature 1 listed above is incorporated herein in its entirety by reference thereto.
In Patent Literature 1, the memory cell group, for which the write time is reduced, is configured to store write data and is not configured to store error-correction information. Here, the write data means one of normal information, i.e., information supplied to a chip terminal from the outside when used by a user. This write data is different from error-correction information.
Patent Literature 1 does not make any reference to a technology relating to error-correction (i.e., ECC: Error Check and Correction) and an application to error-correction technologies.
In Patent Literature 1, a write current is uniformly supplied in the first direction in the memory cell group storing the normal information regardless of the initial state thereof. Therefore, for instance, even when the same data is written on a memory cell with the magnetization direction initially in a parallel state, a current must be supplied in a parallel state after a write current is supplied in an antiparallel state. As a result, when the technology disclosed in Patent Literature 1 is applied, a consumption current of the magnetic random access memory storing the normal information increases.